Attachment for sewing machines



Dec, 8, 1936.y f J. D. KARLE 2,063,844

I ATTACHMENT FOR SEWING MACHINES Filed Dec. 2o, 1934 2 sheets-sheet 13mm/m Joh/xn D; Karle Dec. 8, 1936.

J. D. KARLE ATTACHMENT FOR SEWING MACHINES Filed neg. 2o, 19574 John I7.Earle 2 Sheecs-Sheerl 2 Patented Dec. 8, 1936 UNE STATS slr.

ATTACHMENT FQR SEWHNG MACHINES Application December 20, 1934, Serial No.'758,331

6 Claims.

This invention relates to attachments for sewing machines and moreparticularly to attachments for vibrating the work relative to theneedle and laterally of the line of seam formation to produce zigzagstitches The several features of the present invention will be clearlyunderstood from the following description and accompanying drawings inwhich:

Figure 1 is a front elevation showing a portion of a sewing machine withmy improved attachment fixed thereto.

Figure 2 is a rear elevation.

Figure 3 is a side elevation looking from the right of Figure 1.

Figure 4 is a top plan view.

Figure 5 is a disassembled perspective view of the pawl and two-partneedle-bar actuated lever.

My improved attachment is shown applied to a well known Singer familytype machine having the usual spring-pressed presser-bar reciprocatingneedle-bar 2, needle-clamp 3, needle li, and feed-dog 5.

In its preferred embodiment the attachment comprises a channel block 6adapted to be secured by the fastening screw 'i to the lower portion ofthe presser-bar i. Carried by the block 6 is a plate 3 having anupstanding inclined arm 8 and a cross arm 9 formed with elongatedapertures i l) and outwardly projecting lips which form a guidingchannel. Slidably held in the guiding channel by the rivets l2 is a barI3 having a depending portion lll to which is secured by means of thescrew l5 a presser-foot iii formed with an elongated needle-aperture l5.

Pivotally secured to the upstanding arm 8 of the piate 8 by the pivotpin'l is a swingable member |13 having a laterally extending portion i9provided with a stud I9. The swinging member i3 has an opening 23 withinwardly extending projections 25 and E5 adapted to embrace and engage acam element 26 having a plurality of circumferentially `spacedprojections. Fixed to the cam-element 26 is a ratchet-wheel 28, and thecam-element and ratchet-wheel are rotatably mounted on the lplate i! bymeans of a bearing pin 2S.

Pivotally secured to the arm 8 by the pivotpin 30 is a lever 3| (Fig. 5)formed with an apertured free end 32, a forwardly extending arm 33 and arearwardly extending arm Sli. A lever 35 having a forwardly extendinglip 33 and a rearwardly extending portion 3l is pivotally secured to theend 32 of the lever 3| by the internally threaded pivot-stud 33 on thepawl 39 (Fig. 5). It will be understood that the stud 3S passes (el.i12- 160) through the aperture 4i! in the lever 35 and the aperture litin the lever 3| and is held in position by the screw di. A helicallywound spring i2 reacts between the arm 33 on the lever 3| and the pawl39 to constantly urge the pawl in a v5 clockwise direction about itspivot-stud 38.

A spring i3 embraces the spacing sleeve 44 and has one of its endsacting against the arm 8 and its other end against the portion 31 of thelever 35. The spring i3 urges the lever 35 in a clockwise 10 directionabout its pivot, the movements being limited by the nose on the lever 35which engages the rearwardly extending arm 34 on the lever 3|. Thespring 43 also urges the levers 3| and 35 and the pawl 39 in acounter-clockwise 15 direction about the pivot-pin 30, this movementbeing limited by the arm 3&3 which engages the arm 8. From the foregoingit will be observed that the levers 3| and 35 are in effect a two-partpawl-carrying lever. '20

A nger-lever lili is provided for rendering the attachment inactive atthe will of the operator. This expedient is shown and described inPatent No. 2,003,200, dated May 28, i935.

Made integral with the cross-arm 9 is an upstanding arm il having abell-crank lever 48 pivotally secured to its upper end by the pivot-pin49. One arm of the bell-crank lever is bifurcated to receive the stud I9carried by the swingable member I8 and the other arm is formed with anarcuate slot 50. A pitman 5| connects the bellcrank lever 43 to theslide-plate i3 and has one of its ends adjustably secured in the slot 50by the screw 52 and its other end pivotally secured by the pivot-pin 53to the slide-plate |3.

Operation On the upward movement of the needle-bar, the needle-clamp 3engages the projection 36 on the lever 35 and moves the lever 3| andpawl 39 upwardly. During the movement the pawl 39 engages theratchet-wheel 28 and advances it one step or one-eighth of a revolution,it being understood that the distance the pawl travels on each upstrokeof the needle-bar is slightly greater than the distance between theteeth on the ratchet-wheel. The cam-element 26 being fixed to theratchet-wheel 28 is also moved one-eighth of a revolution. The rotationof the cam-element causes one of its circumferentially spaced projec- 50tions to Contact the inwardly extending projections 25 on the swingingmember I8 causing it to swing in a clockwise direction about its pivotil. This swinging movement causes the pin I9 to swing the bell-cranklever 48 in a counter-clock- 55 Wise direction about its pivot 49. Thismotion is imparted to the slide-plate I3 by means of the pitman 5Ithereby causing the presser-foot I6 to move to the left to the positionshown in Fig. 1. The shifting of the presser-foot I6 occurs while theusual feed-dog 5 is below the throat-plate 55 and is completed justprior to the point of the cycle when the feed-dog contacts the work.After the feed-dog 5 has advanced the work, the needle descends, formingthe stitch and on the upstroke of the needle, the needle-clamp 3 againengages the forwardly extending portion 36 of the lever 35 and moves thelever 3I and pawl 39 in a counter-clockwise direction about the pivot30, the pawl again advancing the ratchet-wheel oneeighth of arevolution. This movement of the ratchet-wheel causes the cam 26 toshift the swingable member I8 in a counter-clockwise direction about itspivot and this movement is irnparted to the slide-plate I3 by means ofthe pin I9', bell-crank lever 48 and pitman 5I. The slideplate I3 andpresser-foot I6 are thereby shifted to the right. From the foregoing itwill be observed that in the rotation of the cam-element 26, itsperipheral projections successively engage the projections of theswinging lever I8 to vibrate the same and thus reciprocate theslide-plate and presser-foot laterally of the line of seam formation. Itwill be obvious that the amount of movement of the slide-plate I3 may bevaried by adjusting one end of the pitman 5I in the arcuate slot 50 ofthe bell-crank lever 48.

This construction provides an adjustment for varying the lateralshifting movement imparted to the presser-foot which can be quickly andeasily made and translates the arcuate movement of the pin I9 to a rightline movement without using a lost motion connection between theswinging member I8 and sliding plate I3, thereby reducing the operatingnoise of the attachment by eliminating the hammer blow. Further,overthrow of the presser-foot under speed is prevented.

It has been found that when an attachment of this type is fixed to thepresser-bar with the needle-bar clamp in its highest position, the lip36 on the pawl-carrying lever is disposed beneath the needle-clamp withthe result that, upon operation of the machine, the needle-clamp on itsdown stroke will strike the lip 3S and damage the attachment. Toovercome this diiculty, the pawl-carrying lever is made in two parts (3|and 35) which are pivoted together and the lever 35, which is engaged bythe needle-bar clamp, is spring-urged about its pivot in a clockwisedirection by the spring 43 and its movement is limited by the stop 45and arm 34.

With this arrangement, if the attachment is inadvertently attached tothe machine with the end of the pawl-carrying lever in a position toy beengaged by the needle-clamp on its downward stroke, upon operation ofthe machine the free end of the lever 35 will yield to permit theinitially descending needle-clamp to pass. After the needle-clamp haspassed, the lever will assume its operative position due to theinfluence of the spring 43.

Having thus set forth the nature of the invention, what I claim hereinis:-

1. A zigzag-stitching attachment comprising a. member adapted to besecured to the presserbar of a sewing machine, a frame carried by saidmember, a slide-plate carried by said frame, a swingable member carriedby said frame, a cam for vibrating said member, ratchet and pawl meansfor actuating said cam, a bell-crank lever pivoted to said frame andactuated by said swingable member and means for connecting saidbellcrank lever to said slide-plate.

2. A zigzag-stitching attachment comprising a member adapted to besecured to the presser-bar of a sewing-machine, a frame carried by saidmember, a slide-plate carried by said frame, a swingable member pivotedto said frame, a cam for vibrating said member, ratchet and pawl meansfor actuating said cam, a bell-crank lever pivoted to said frame andactuated by said swingable member and a pitman having one of its endsadjustably connected to one of the arms of said bell-crank lever and itsother end pivotally connected to said slide-plate.

3. A zigzag-stitching attachment comprising a member adapted to besecured to the presserbar of a sewing machine, a frame having anupstanding arm and a cross-arm formed with a channel secured to saidmember, a slide-bar carrying a presser-foot tted in said channel, aswinging lever fulcrumed on the upstanding arm of said frame, a campivoted to the upstanding arm of said frame for actuating said swinginglever, means for actuating said cam, an upstanding arm carried by thecross-arm of said frame, a bell-crank lever pivoted to said arm andhaving one of its arms operatively connected to said swinging lever anda pitman connecting said slide-bar to the other arm of said bell-cranklever.

4. An attachment for sewing machines having a vibratory work-engagingmember and means for vibrating said member, said means including a cam,and a ratchet and pawl for actuating said cam, said pawl being carriedby a two part pivoted lever composed of relatively yielding parts.

5. In combination with a sewing machine having a needle-bar and apresser-bar, a frame secured to said presser-bar, a slide-plate carryinga presser-foot mounted on said frame, a swingable member pivoted to saidframe, a cam for actuating said member, and means for actuating saidcam, said means comprising a ratchet fixed to said cam, a lever pivotedto` said frame, a second lever pivoted to the first mentioned lever andhaving a stop to limit its movement in one direction relative to thefirst mentioned lever, a spring for yieldingly urging said second leveragainst said stop, and a pawl carried by said lever for actuating saidratchet-wheel.

6. An attachment comprising a frame adapted to be secured to thepresser-bar of a sewing machine, a slide-plate and presser-foot carriedby said frame, a swingable member pivoted to said frame, a bell-cranklever actuated by said swingable member, a connection between thebell-crank lever and said slide-plate, a cam in operative engagementwith said swingable member, a ratchet-wheel carried by said cam, aneedle-bar actuated two-part lever pivoted to said frame and having ayieldable free end and a pawl carried by said lever for imparting astep-by-step movement to said ratchet-wheel.

JOHN D. KARLE.

